Exam 3: Basic Embryology

As a result of folding, the embryo acquires a tadpole shape by

Figure 3.1 Use the diagram above to answer the following questions. -Which letter indicates the morula?

This develops into the brain and spinal cord.

A primitive characteristic that an adult human retains only in part, but is important in determining bilateral symmetry is the ________.

The inner cell mass will form the embryo, and the trophoblast will form the placenta.

Division of cells in a zygote is called

Neural crest cells are derived from this germ layer.

A teratogen is

Chemical, physical, or biological agents that can induce birth defects are called

Describe the types of tissues that make up the endoderm, ectoderm, and mesoderm, and explain how these tissues relate to their developmental processes.

The ability of one cell to influence the development of its neighboring cells is called

The splanchnic mesoderm forms next to this layer.

A transverse section through the 24-day embryo, dorsal to ventral, would first contact the

Somites differentiate into

The urinary bladder is derived from which embryonic layer?

The primary germ layer that ultimately produces the hair, fingernails, and toenails is

The fetal period is the longer and later of the prenatal growth periods.

The embryonic layer that invades the lining of the uterus and forms the placenta is the

The sclerotome will develop into the

Define the term teratogen, and explain why exposure to teratogens during the first 8 weeks of pregnancy is particularly dangerous.